HARARE, Zimbabwe — Armored personnel carriers have been seen outside the capital of Zimbabwe a day after the Army commander threatened to “step in” to calm political tensions over the president’s firing of his deputy. The Associated Press saw three APCs with several soldiers in a convoy on a road heading toward an Army barracks just outside Harare. While it is routine for APCs to move along that route, the timing heightened unease in this southern African country that for the first time is seeing an open rift between the military and 93-year-old President Robert Mugabe. The military has been a key pillar of Mugabe’s power since independence from white minority rule in 1980. Mugabe last week fired Vice President Emmerson Mnangagwa and accused him of plotting to take power, including through witchcraft. Mnangagwa, who enjoyed the backing of the military and was once seen as ...